The Metabolic Syndrome (MetS) is a common problem among Veterans and is associated with a greater likelihood of cardiovascular disease (CVD). The Mediterranean diet is the only popular diet that has been shown to reduce CVD event rates but the extent to which monounsaturated fatty acid (MUFA) or polyunsaturated fatty acid (PUFA) enrichment results in improvement in parameters of MetS is unresolved. Similarly, while low intensity exercise improves the CVD risk factor profile, there have been no comparative investigations comparing MUFA and PUFA enriched diets and exercise in patients with MetS that have extended beyond 1 year. Recently, the VA established the MOVE! program, a national weight management program designed to help Veterans lose weight. Using the VA promoted program, we will perform a systematic evaluation of the effects of dietary fat composition [comparison between MUFA-enriched and PUFA enriched diet] with MOVE!. We hypothesize that a MUFA-enriched diet consisting of antioxidant, lipid reducing and insulin sensitizing properties will be superior to the less palatable PUFA- enriched diet on improving cardiometabolic parameters associated with MetS. Specifically, the MUFA MOVE! program is expected to lead to greater improvements than the PUFA MOVE! program in body composition and aerobic fitness (Specific Aim 1), endothelial dependent flow mediated vasodilation and the postprandial lipid response to a meal load (Specific Aim 2) and the mechanisms (lipolytic and lipid transfer protein activity, homeostasis model assessment-estimated insulin resistance) responsible for these effects (Specific Aim 3). Collectively, these studies will advance our understanding of mechanisms underlying the differential effects of MUFA and PUFA-enriched dietary regimens on cardiometabolic health and when combined with the MOVE! program, will provide new and useful information to Veterans (and the general public) interested in optimizing their diets for CVD disease prevention and improved vascular health.